Method of controlling wool shrinkage and products thereof



United States Patent 3,223,473 METHUD OF CONTROLLING WGOL SHRINK- AGE AND PRQDUCTS THEREOF Werner Von Bergen, North Caldwell, and Harold W. Wolf, Clifton, NJ, assignors to J. P. Stevens 8; Co. Inc., New York, N.Y., a corporation of Delaware N0 Drawing. Filed May 15, 1962, Ser. No. 14,977 4 Claims. (Cl. 8-128) This invention relates to a method of controlling wool shrinkage in textile materials made of wool or of wool and other fibers and to the product resulting therefrom.

It is known that dilute solutions of potassium or sodium permanganate will reduce the shrinkage or felting characteristics of Wool. Ordinarily, the permanganate solutions used to treat the wool are acid in character. However, methods devised for controlling wool shrinkage involving the use of the permanganate ion at temperatures of about 100 C. or below do not produce a wool possessing satisfactory characteristics. This is due to the fact that the reaction of the permanganate solution with the wool is largely at the surfaces of the Wool fibers and does not penetrate to any considerable extent within the wool fibers. Where surface active or wetting agents are employed to increase penetration, shrink-proofing is enhanced but only at the sacrifice of the natural feel or hand of the wool.

Accordingly, it is an object of the present invention to provide an improved method of shrink-proofing wool or of controlling wool shrinkage at temperatures less than 100 C. by subjecting the wool to a method of treatment that can be readily controlled and that produces a wool which retains its natural feel and hand.

A further object of this invention is to provide a method of controlling wool shrinkage by a continuous process whereby alkaline permanganate solutions are used in conjunction with selected wetting agents which do not bring about a degradation of the permanganate solutions.

A further object of this invention is to provide wool and wool-containing fabrics having a superior texture and hand than similar fabrics treated by presently known resin, chlorination, and oxidative processes.

These and other objects will be apparent from the description which follows.

According to the present invention, shrink-resistant wool or wool-containing fabrics are obtained by treating said fabrics with a permanganate that is slightly alkaline together with selected surface active or wetting agents of the dialkyl sulfosuccinate type which bring about a rapid penetration without degradation of the permangante solution into the fabrics in a relatively short time depending upon the porosity of the fabrics treated and the degree of shrinkage resistance desired.

More specifically, the present invention contemplates passing the wool or wool-containing fabric into a treating tank consisting of an alkaline solution of an alkali metal permanganate and a dialkyl sulfosuccinate as is well known in the art to apply solutions to woolen goods by immersion. By proper adjustment of the size of the treating tank and arrangement and number of immersion rolls, the rate of passage can be completed at practically any desired rate. Therefore, where conditions are such that production requirements are small, treatment can be made in an immersion bath of small capacity; i.e., 2 or 3 dips at a rate of 3 to 4 yards per minute. However, it will be found more practical and efficient to treat the fabrics at a higher throughput using increased length of bath and number of clips to give a production of at least 25 to 30 yards per minute which can be achieved by a series of 5 immersion rolls prior to the squeeze rolls.

It has been found that a satisfactory range of operation 3,223,473 Patented Dec. 14, 1965 is to employ potassium permanganate (or sodium permanganate) at a concentration of 0.3 to 0.6% on the weight of solution (O.W.S.), a temperature from ambient room temperature up to 93 C., and a pH of 7.5 to 8.5 with the addition of 0.05 to 0.1% dialkyl sulfosuccinate (O.W.S.). A preferred concentration of alkali metal permanganate is 0.5% (O.W.S.) at a temperature of 27 C. to 32 C. with 0.8% dialkyl sulfosuccinate whereby the pH is maintained at 7.7 and the fabric is contacted for about 20 seconds. An operative alkalinity range for the permangante solution is from 7.1 to about 9.0 pH with a concentration of 0.2 to about 1.0% O.W.S. Where higher temperatures are employed, the reaction of the treating solution with the wool or wool-containing fabric will take place more rapidly. In general, the treatment of the fabric can be carried out in seconds ranging from 12 to 30 and preferably 20 to 21 seconds depending upon the porosity of the fabrics being treated and the degree of resistance to laundering shrinkage desired.

After the oxidative treatment in a stabilized alkaline permanganate, the treated wool or wool-containing fabric is passed immediately through a warm (preferably 43 C. to 52 C.) reducing solution containing 1 part sodium sulfite and 1 part sodium bisulfite at a total solids concentration of 15 to 35% but preferably 30%. While it is possible to carry out this second step in batchwise fashion, the recommended and preferred method is to use a continuous treatment in the reductive bath whereby the fabric emerging from the oxidative permanganate solution through the squeeze rolls immediately enters a second control bath containing sulfite-bisulfite reducing agents for a minimum contact period of 20 seconds, depending upon the construction of the fabric, concentration of the chemicals, and operating temperature. In general, the looser the fabric, the higher the concentration of chemical, and the higher the operating temperature, the shorter will be the contact time.

The wool or wool-containing fabrics treated by the above procedure were noted to have outstanding properties with regard to resistance to laundering shrinkage. In addition, the wool or wool-containing fabrics treated by the process of this invention were observed to have a superior hand. Fabrics treated by the process of this invention included wool flannels of various grades and weights, fabrics containing wool and synthetic fibers such as wool-nylon blends, and fabrics which contained dyed fiber prior to treatment, as well as those which were natural colored fabrics but piece-dyed; i.e., after chemical treatment. Strength of the treated wool or wool-containing fabrics as measured by Scott tests and abrasion tests by Universal Flexibrater and chemical damage as tested by A.S.T.M. alkali solubility method were very acceptable.

Various modifications can be made in the process of this invention. For example, a treating solution can be applied to the wool or wool-containing fabrics by padding or spraying. Although the preferred wetting or surface active agent is dioctyl sulfosuccinate, sulfosuccinates of the following general formula can be employed:

ngooooni NHOZSC COOR2 wherein R and R are alkyl groups having 1 to 8 carbon atoms. Sulfosuccinates of this type are known and have been previously described in the literature (see US). Patent Nos. 2,028,091 and 2,176,423).

The present invention will be more completely understood by reference to the following examples. In each instance all parts and percentages are by weight unless otherwise specified.

Example 1 A wool-nylon fabric (85% wool+l5% nylon) was dipped 3 times for a total immersion period of 20 secends in a treating solution consisting of lbs. of dioctyl sulfosuccinate and 50 lbs. of potassium permanganate each in 1200 gallons of water (average concentration of the potassium permanganate 0.483%). The temperature of the treating solution was 32 C. while the pH of the solution was 8.5. The linear speed of the speed of the fabric through the treating solution was 15.5 yds. per minute such that 400 lbs. of fabric were treated in about 1 hour. The fabric so treated was then passed through a reducing solution consisting of sodium sulfite plus 15 sodium bisulfite on the Weight of fabric (O.W.F.) at 49 C. followed by two water rinses. Treated fabrics were thereafter given 5 Wash-and-wear launderings and the shrinkage control was found to be 1.5% warp and 1.0% filling in contrast to the untreated fabric which was 12% warp and 7% filling. The alkali solubility was 22.7%.

Example 2 The procedure of Example 1 was repeated with the same excellent results except that the fabric was 100% wool flannel, the average concentration of the potassium permanganate solution was 0.497%, the pH 7.8, and the temperature was 31 C.

While the illustrative embodiments of the invention have been described hereinbefore with particularity, it will be understood that various other modifications will be apparent to and can readily be made by those skilled in the art without departing from the scope and spirit of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and description set forth herein but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present invention including all features which would be treated as patentable equivalents thereof by those skilled in the art to which the invention pertains.

What we claim is:

1. A process for shrink-proofing wool and wool-containing fabrics comprising treating said fabrics at a temperature below C. with a stable alkaline solution comprising an alkali meta-l permanganate in a concentration of about 0.2% to about 1.0%, based on the weight of the solution, and a permanganate non-degrading dialkyl sulfosuccinate.

2. A process for shrink-proofing wool and wool-containing fabrics comprising treating said fabrics for a period of about 12 to 30 seconds at a temperature below 100 C. with a stable alkaline solution comprising an alkali metal permanganate in a concentration of about 0.2% to about 1.0%, based on the weight of the solution, and a permanganate non-degrading dialkyl sulfosuccinate.

3. A process for shrink-proofing wool and wool-containing fabrics comprising treating said fabrics at a temperature below 100 C. with a stable alkaline solution comprising an alkali metal permanganate in a concentration of about 0.2% to about 1.0%, based on the weight of the solution, and containing as a stabilizer for the permanganate a permanganate non-degrading dialkyl sulfosuccinate having the formula,

H20 COORr NaO SC COOR:

wherein R and R are alkyl groups having 1 to 8 carbon atoms.

4. The process as defined in claim 3 wherein the dialkyl sulfosuccinate is dioctyl sulfosuccinate.

References Cited by the Examiner UNITED STATES PATENTS 2,028,091 l/1936 Jaeger 260481 2,176,423 10/1939 Jaeger 260-481 2,257,076 9/1941 Petke et a1. 81 l1 FOREIGN PATENTS 638,580 6/1950 Great Britain.

NORMAN G. TORCHIN, Primary Examiner. 

1. A PROCESS FOR SHRIN-PROOFING WOOL AND WOOL-CONTAINING FABRICS COMPRISING TREATING SAID FABRICS AT A TEMPERATURE BELOW 100*C. WITH A STABLE ALKALINE SOLUTION COMPRISING AN ALKALI METAL PERMANGANATE IN A CONCENTRATION OF ABOUT 0.2% TO ABOUT 1.0%, BASED ON THE WEIGHT OF THE SOLUTION, AND A PERMANGANATE NON-DEGRADING DIALKYL SULFOSUCCINATE. 